Thermostatic apparatus



Fig. 2, showing the parts in a different posi- Patented July 5, 1927.

UNITED STATES 1,634,379 PATENT OFFICE.

JOSEPH W. MYERS, OF JACKSbN, MICHIGAN, ASSIGNOR, BY DIRECT AND MESNE AS- SIGNMENTS,

0F ONE-THIRD T0 JOSEPH H. MYERS, OF JACKSON, MICHIGAN; ONE- THIRD 'IO ARTHUR J. 'IUT'ILE, OF DETROIT, MICHIGAN; AND ONE-THIRD TO AGNES W. MYERS AN DJ OSEPH-W. MYERS, BOTH OF JACKSON, MICHIGAN.

THERMOS'IA'IIC APPARATUS.

Application filed December 20, 1923. Serial No. 681,751.

My invention relates to electrically heated fiatirons and consists in the improvements hereinafter described and pointed out in the claims.

In the accompanying drawings Fig. 1 is aside elevation of an iron embodylng my invention.

Fig. 2 is a p1an view to an enlarged scale, with the cover removed. 4

Fig. 3 is a detail plan view similar to tion.

Fig. 4 is a longitudinal centralsection.

. Fig. 5 is a detail showing one of the spring arms separate from the rest of the construction.

Fig. 6 is a detail plan view showing a modified construction at the end of the spring-arms.-

Fig. 7 is a view similar to Fig. 6 showing a second modification.

Fig. 8 is a sectional detail view the section being taken on the line VIII-VIII Fi ire 2.

ig. 9 is-a detail plan. view to an enlarged scale showing the construction of the bimetallic thermostatic arms.

a, is the body of the iron, and b the handle-a, is the sole plate, and a a projection rising from the forward part of the plate at I make the projection a of good heat conducting material such as copper and joinit to the plate a, so that heat will readily ass from the plate to said projection, or t e projection may be made integral with the plate and of the-same material.

In slots cut into the lug a, from itsupper end I place bimetallic thermostatic arms 0, 0, so that they shall extend toward the rear of the iron and slightly diverge from each other. These arms are forced tight into said slots so as to form a. joint-with the lug a through which heat will readily pass. Each of said arms is made up of a plurality'of thin bimetallic thermostatic strips, so that the relative large movement of a thin strip may be secured, while by using a number of strips 0, a the strength of action of a thick strip is secured, (1, (P, are similar spring arms, one of which is secured at one end to the outer end of each of the arms, a, c, and is electrically insulated therefrom and forms an extension thereof. 6, e, are electrical conductors by which an electric current is conveyed to and away from the arms d, d. Rods 1-, T are secured to the outer ends of said arms and extend toward each other and are provided with contact pieces (1, d, at their adjacent and contiguous ends.

Under normal conditions the arms d, (1 press the points d d into contact with a yielding pressure owing to the elasticity of said arms, but should the iron become too hot the thermostatic arms 0 0 would be caused to diverge by the heat imparted to them which would force the arms d, d apart and separate the contact points d, d, whereby the heating circuit of the iron would be broken. I

f. is an elastic arm connected at one end to the arm dand connected arm 0, extending toward the rear of the iron and diverging toward the arm (P; f, is an arm similar to the arm f, but secured to the arm 03.

g, is a rod bearing in, and extending through, the upper horizontal wall of the cover of the iron and adapted to be turned about its axis in said bearing. g 9 ,is a double cam secured to the lower end of the rod 9, between the arms f, f and adapted to engage against said arms to force them apart when the rod 9 is turned. 9, is a thumb-piece on the upper end of the rod 9 by which said rod may be manipulated.

The thumb-piece g, is located beneath the center of the handle 7),. and is provided with a pointer g which moves over a scale g. By turning the rod 9 to a greater or less extent the cams g g are made to develop the elasticity of the arms 7, f to a greater or less extent which counteracts the elastic force with which the arms 03, d press the points at, d, together. Thus by turning the thumb-piece g, the elastic force that it is necessary for the thermostatic arms 0, c, to exert to break the circuit may be regulated and consequently the temperature at which the heating circuit is automatically broken may be selected.

Sometimes the points d, d, will stick together at some points of their contiguous surfaces. When the arms (2, d are acted upon by the arms 0, 0, the curvature of the arms at, d is altered because of their elasticity which rocks the surfaces of the contacts d, (2 upon each other, thus prying the sticking points of said surfaces apart. To increase this rocking action the arms d, 03 are made smaller at their ends adjacent to the contact points as shown for example, from d to d in Figure 5.

It=-is desirable to have the points 03 ,11 separate positively, surely and quickly. To accomplish this object I provide an automatically operated mechanical means, supported by the arms (l, 61 at their outer ends for causing the rompt and certain separating of said points. This is described as follows:

it, is a metal strip secured to, but insulated from the rod r, 15. is a similar strip similarly secured to the rod 7*. The strips k, 72,2 are bent inward as shown and their free ends are formed to present hollow grooves toward each other and approxi-* mately in a vertical plane through the longitudinal axis of the iron, into which grooves the ends of the plate y are placed. The strips h k are so shaped and located that they develop an elastic force in the arms d, (1 pressing against the ends of the plate j. Under normal operative conditions the plate j is located as shown in Figure 2, so inclined to the forces upon its ends that it tends to force the points d (2 closer'together. When the working temperature of the iron is exceeded the arms 01, d, are flexed so as to carry the ends of the plate 7', by the line of the forces on its ends, as shown in Figure 3, and this plate then acts to force the points d, d, quickly and certainly apart.

Instead of utilizing the elasticity of the arms d, (2 to act upon the plate j, as above described, the strips h, 71. of Figure 6 may be used which are themselves elastic.

A third construction is shown in Figure 7, in which the plate 7' is extended backward in a part 9', and the contact point at, is placed on the rear end of said extension to engage with the contact point distance from the outer end of the arm (1 The ends of the arms (1 and d are here bent toward each other and provided with grooves to engage the 'ends of the plate j, and bring a pressure on its ends for the purpose described.

I provide a switch in the handle of the iron by which the heating current may be turned on or shut off at the will of the operator.

b, is a contact switch of suitable construction located in the handle of the .iron and interposed in the heating circuit 6 is a rod extending vertically through apertures in one end of the handle 15, one of its ends appeering below the handle and the other above the same. The rod 6 is connected within the handle and intermediate the ends of said rod with one arm of the switch I). The word On i p ced at upp r nd located at a little 'said arm being so locate of said rod, and the word Ofi at the lower end thereof. When the rod 6 is at the lower end of its travel the switch I) has interrupted the circuit and the word Off is displayed conspicuously to view. When said rod is at the other end of its travel, the switch 6, has completed the circuit and the word On appears above the handle-b and b are notches in the side of the rod 6 b is a piece of spring steel bent in the form shown and presenting at proper points the salient loops b and b adapted to engage in the notches b and 6 When the rod 6 is at the upper end of its travel the loop 6 engages in the notch b and holds said rod in position. When the rod is pressed down the loop 6 engages in the notch b" and holds the rod in this position.

What I claim is:

1. In a thermostatic switch with two cooperating electrical contacts, two mutually opposing resilient arms in cooperative relation to each other and said contacts, means permanently connected to each of said arms and acting between said arms to control the motion thereof and accelerate the same adjacent to the contact position.

2. In an electric iron having a cover and having a thermostat adapted to re ulate the temperature of the iron, 9. vertical rod projecting through the cover of said iron and carried by said cover, said rod being adapted to be turned from without the iron, a cam carried by said rod on the inside of said cover adapted to enga e a temperature regulating member of sai thermostat in such a manner as to actuate said regulating member upon rotation of said rgfd, said thermostat being wholly fixed to sai iron and said rod being removable with said cover.

3. In a switch the combination of two movable arms carrying contacts, oneof said arms being flexible, a part permanently connected to each of said arms lying approximately parallel to said flexible arm and pivotally.engaging one of said arms at a oint at one side of its axis at one end and eing pivotal ly en aged at the other end so that said arm is nt by the action of said art and exercises because of its resilience a ongitudinal force upon said art, said part and that a movement of said arm shall carry said part over its center to secure a quick break of contact.

7 4. In an electric iron having a cover and having a thermostat adapted to re ulate the temperature of said iron, 9. vertica rod projectmg through the cover of said iron and carried by said cover, said rod being adapted to be'turned from without the iron, said rod being adapted to engage a temperature regulating member of said thermostat in such a manner as to actuate such regulating member. upon rotation of said rod, said thermostgt being wholly fixed to said iron and said rod being removable with said cover. adapted to coact, a thermostat adapted to 10 5. In a switch, the combination of two act upon said flexible arm and a snap-over thermostats, a resilient extension from each member between said contacts adapted to be of said thermostats, contacts carried by said carried over its center by the flexing of said 5 extensions, and a. snap-over member between arm when acted upon by said thermostat.

said resilient extensions. In testimony whereof, I ign thi d- 16 6. In a switch, the combination of a flexfication.

ible arm carrying a contact; a second contact with which the first named contact is I J OSEPH'W. MYERS. 

